218535497 has 2 divisors, whose sum is σ = 218535498. Its totient is φ = 218535496.

The previous prime is 218535479. The next prime is 218535509. The reversal of 218535497 is 794535812.

Together with previous prime (218535479) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 159491641 + 59043856 = 12629^2 + 7684^2 .

It is a cyclic number.

It is not a de Polignac number, because 218535497 - 2⁶ = 218535433 is a prime.

It is not a weakly prime, because it can be changed into another prime (218535437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109267748 + 109267749.

It is an arithmetic number, because the mean of its divisors is an integer number (109267749).

Almost surely, 2^218535497 is an apocalyptic number.

It is an amenable number.

218535497 is a deficient number, since it is larger than the sum of its proper divisors (1).

218535497 is an equidigital number, since it uses as much as digits as its factorization.

218535497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 44.

The square root of 218535497 is about 14782.9461542684. The cubic root of 218535497 is about 602.3385558266.

The spelling of 218535497 in words is "two hundred eighteen million, five hundred thirty-five thousand, four hundred ninety-seven".